Strong Geomagnetic Storm in Progress

Spaceweather.com reports a strong geomagnetic storm is in progress as Earth passes through a region of south-pointing magnetism in the solar wind. The storm has generated auroral displays as far south as Kansas in the US. The NOAA Space Weather Prediction Center indicates the storm is a G3 level event. WWV announced at 0900 UTC, “Geomagnetic storms reaching the G3 level are likely” over the next 24 hours. NOAA says that in a G3 level storm, HF radio may be intermittent. Calculated band conditions reported on the DX Summit site indicate “poor” conditions on 80 through 10 meters. WWV reported the estimated planetary K index at 0900 UTC was 5 (the 0600 UTC figure was 7). As Carl Luetzelschwab, K9LA, explains, “The A index is an average of the eight 3-hour K indices, and uses a linear scale and goes from 0 (quiet) to 400 (severe storm). The K index uses a quasi-logarithmic scale (which essentially is a compressed version of the A index) and goes from 0 to 9 (with 0 being quiet and 9 being severe storm). Generally an A index at or below 15 or a K index at or below 3 is best for propagation.” In recent hours the A index has been 22, and the K index has ranged from 5 to 7. As of 0900 UTC, the sunspot number was 83, and the solar flux index was 100. Spaceweather.com predicts, “When the current spate of geomagnetic storms is over, another could follow close on its heels.” A coronal mass ejection (CME) is expected to deliver a glancing blow to Earth’s magnetic field late on June 30 or early on July 1.